<!DOCTYPE html>
<html lang="en" xmlns:wicket="http://www.w3.org/1999/xlink">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    This is in the child markup. <br/>

    <wicket:extend>
        This is in the child markup. <br/>
    </wicket:extend>
    This is in the child markup. <br/>

</body>
</html>